It is known that a polymer prepared from a polymerizable compound having a perfluoroalkyl or perfluoroalkenyl group and an acrylate or methacrylate group is useful as a water- and oil-repellent agent used for a textile and woven fabric. Particularly an aqueous dispersion wherein said polymer is dispersed in an aqueous medium with a surfactant is industrially and widely used.
Generally, emulsion particles have the ionicity caused by a surfactant obtained by combining a cationic or anionic surfactant with a nonionic surfactant for the purpose of giving a stable dispersion. In this case, there is the problem that the properties are rapidly worsened in a latter half of treatment by selective absorption of particles to a woven fabric, and in the case of using different ionic agents for a treatment liquid, there is the problem that a dispersion liquid is broken to generate agglomerated cakes of polymer which troublously makes stains of the processed fabric by attachment of agglomerated cakes to the processed fabric.
In order to solve above problems, JP-B-53-4159 proposes that a nonionic surfactant having an HLB of 15 to 20 and is used in aqueous medium in an amount of at least 40% by weight. However, a storage stability and a stability at dilution use are remarkably poor, and performances (particularly water- and oil-repellency) also are poor.